It can be noticed that unlike Eclipse ADT (App Development Tools), Android Studio doesn’t contain an Assets folder in which we usually use to keep the web files like HTML. Assets provide a way to add arbitrary files like text, XML, HTML, fonts, music, and video in the application. If one tries to add these files as “resources“, Android will treat them into its resource system and you will be unable to get the raw data. If one wants to access data untouched, Assets are one way to do it. But the question arises is why in the asset folder? We can do the same things by creating a Resource Raw Folder. So let discuss how the assets folder is different from the Resource Raw folder?
How the asset folder is different from the Resource Raw folder?
In Android one can store the raw asset file like JSON, Text, mp3, HTML, pdf, etc in two possible locations:
- assets
- res/raw folder
Both of them appears to be the same, as they can read the file and generate InputStream as below
// From assets
assets.open(assetPathFilename)
// From res/raw
resources.openRawResource(resourceRawFilename)
But when to use which folder?
Below is some guidance that might be helpful to choose
1. Flexible File Name: (assets is better)
- assets: The developer can name the file name in any way, like having capital letters (fileName) or having space (file name).
- res/raw: In this case, the name of the file is restricted. File-based resource names must contain only lowercase a-z, 0-9, or underscore.
2. Store in subdirectory: (possible in assets)
- assets: If the developer wants to categories the files into subfolders, then he/she can do it in assets like below.
- res/raw: In this case, files can only be in the root folder.
3. Compile-time checking: (possible in res/raw)
- assets: Here, the way to read it into InputStream is given below. If the filename doesn’t exist, then we need to catch it.
assets.open(“filename”)
- res/raw folder: Here, the way to read it into InputStream is:
resources.openRawResource(R.raw.filename)
So putting a file in the res/raw folder will provide ensure the correct file-name during compile time check.
4. List filenames at runtime: (possible in assets)
- assets: If the developer wants to list all the files in the assets folder, he/she has used the list() function and provide the folder name or ” “ on the root folder as given below.
assets.list(FOLDER_NAME)?.forEach {
println(it)
}
- res/raw: This is not possible in this folder. The developer has to know the filename during development, and not runtime.
So, in assets, one can read the filename during runtime, list them, and use them dynamically. In res/raw, one needs to code them ready, perhaps in the string resources file.
5. Filename accessible from XML: (possible in res/raw)
- assets: No simple way the developer can arrange an XML file (e.g. AndroidManifest.xml) to point to the file in the assets folder.
- res/raw: In any XML files like in Java, the developer can access the file in res/raw using @raw/filename easily.
So if you need to access your file in any XML, put it in the res/raw folder. Let’s make a table to remember the whole scenario easily.
|
Scenario |
Assets Folder |
Res/Raw Folder |
|---|---|---|
| Flexible File Name |
YES |
NO |
| Store in subdirectory |
YES |
NO |
| Compile-time checking |
NO |
YES |
| List filenames at runtime |
YES |
NO |
| Filename accessible from XML |
NO |
YES |
How to Create Assets Folder in Android Studio?
Now let’s discuss how to create an assets folder in the android studio. Below is the step-by-step process to create an assets folder in Android studio.
Step 1: To create an asset folder in Android studio open your project in Android mode first as shown in the below image.
Step 2: Go to the app > right-click > New > Folder > Asset Folder and create the asset folder.
Step 3: Android Studio will open a dialog box. Keep all the settings default. Under the target source set, option main should be selected. and click on the finish button.
Step 4: Now open the app folder and you will find the assets folder by the name of “assets” as shown in the below image.